U.S. patent application number 14/850696 was filed with the patent office on 2016-06-30 for organic light emitting display device.
This patent application is currently assigned to LG DISPLAY CO., LTD.. The applicant listed for this patent is LG Display Co., Ltd.. Invention is credited to Jaehee PARK.
Application Number | 20160190228 14/850696 |
Document ID | / |
Family ID | 53969306 |
Filed Date | 2016-06-30 |
United States Patent
Application |
20160190228 |
Kind Code |
A1 |
PARK; Jaehee |
June 30, 2016 |
ORGANIC LIGHT EMITTING DISPLAY DEVICE
Abstract
Provided is an organic light emitting display device. The
organic light emitting display device includes: a plurality of
sub-pixels including an anode and a cathode; an anode line
configured to supply an anode voltage to the anode; and a cathode
line configured to supply a cathode voltage to the cathode, and in
each of the plurality of sub-pixels, a direction of an anode
voltage input of the anode line and a direction of a cathode
voltage input of the cathode line are different from each other and
face each other in order to reduce a deviation in a potential
difference between the anode and the cathode. Thus, it is possible
to improve uniformity in the potential difference between the anode
and the cathode caused by a line resistance.
Inventors: |
PARK; Jaehee; (Gumi-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG Display Co., Ltd. |
Seoul |
|
KR |
|
|
Assignee: |
LG DISPLAY CO., LTD.
Seoul
KR
|
Family ID: |
53969306 |
Appl. No.: |
14/850696 |
Filed: |
September 10, 2015 |
Current U.S.
Class: |
257/40 |
Current CPC
Class: |
H01L 27/3297 20130101;
H01L 27/3218 20130101; H01L 27/3276 20130101; H01L 27/3279
20130101 |
International
Class: |
H01L 27/32 20060101
H01L027/32 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 31, 2014 |
KR |
10-2014-0196003 |
Apr 30, 2015 |
KR |
10-2015-0061775 |
Claims
1. An organic light emitting display device comprising: a plurality
of sub-pixels including an anode and a cathode; an anode line
configured to supply an anode voltage to the anode; and a cathode
line configured to supply a cathode voltage to the cathode, wherein
in each of the plurality of sub-pixels, a direction of an anode
voltage input of the anode line and a direction of a cathode
voltage input of the cathode line are different from each other and
face each other in order to reduce a deviation in a potential
difference between the anode and the cathode.
2. The organic light emitting display device according to claim 1,
wherein the organic light emitting display device is configured
such that the anode voltage in the anode line is gradually
decreased along the direction of the anode voltage input, the
organic light emitting display device is configured such that the
cathode voltage in the cathode line is gradually increased along
the direction of the cathode voltage input, and a degree of
decrease in the anode voltage in the anode line according to a
distance and a degree of increase in the cathode voltage in the
cathode line according to a distance are set by a line resistance
of the anode line and a line resistance of the cathode line,
respectively.
3. The organic light emitting display device according to claim 2,
wherein the organic light emitting display device is configured to
compensate the deviation in the potential difference between the
anode and the cathode in the plurality of sub-pixels by offsetting
the increased cathode voltage in the cathode line by the decreased
anode voltage in the anode line.
4. The organic light emitting display device according to claim 3,
wherein the line resistance of the anode line and the line
resistance of the cathode line have a difference of less than
10%.
5. The organic light emitting display device according to claim 1,
further comprising: an active area including the plurality of
sub-pixels; and a peripheral area configured to surround the active
area, wherein the anode line is extended from an edge of the
peripheral area to the other edge facing the edge so as to be
connected with the plurality of sub-pixels, and the cathode line is
extended from the other edge of the peripheral area to the edge
facing the other edge so as to be connected with the plurality of
sub-pixels.
6. The organic light emitting display device according to claim 5,
wherein the anode line and the cathode line include one-way input
lines, and the anode line and the cathode line are short-circuited
at a dead-end of the active area.
7. The organic light emitting display device according to claim 6,
wherein the anode line and the cathode line are formed in a comb
shape, and the anode line and the cathode line are configured such
that comb teeth line segments are disposed to cross each other in
the active area.
8. An organic light emitting display device comprising: an active
area including a plurality of sub-pixels; a peripheral area
configured to surround the active area; an anode line disposed from
a first edge of the peripheral area and extended towards a second
edge opposing the first edge so as to supply an anode voltage from
the first edge of the peripheral area towards the second edge to
the active area; and a cathode line disposed from the second edge
of the peripheral area and extended towards the first edge so as to
supply a cathode voltage from the second edge of the peripheral
area towards the first edge to the active area.
9. The organic light emitting display device according to claim 8,
wherein each of the plurality of sub-pixels includes: a driving
transistor including an active layer, a gate electrode, a source
electrode, and a drain electrode; a data line configured to apply
an image signal to the driving transistor; and an organic light
emitting diode driven by the driving transistor and including an
anode, an organic light emitting layer, and a cathode, wherein the
data line is electrically connected with the gate electrode of the
driving transistor, the anode line is electrically connected with
the drain electrode of the driving transistor, and the cathode line
is electrically connected with the cathode of the organic light
emitting diode.
10. The organic light emitting display device according to claim 9,
wherein the image signal applied to the driving transistor through
the data line is an image signal modified to compensate a voltage
Vgs according to an increment in the cathode voltage in the cathode
of each of the plurality of sub-pixels.
11. The organic light emitting display device according to claim
10, wherein the image signal is compensated proportionally to the
increment in the cathode voltage.
12. The organic light emitting display device according to claim 8,
further comprising: at least one circuit board, wherein at least
one circuit board is disposed so as not to be overlapped with a
rear surface of the active area.
13. The organic light emitting display device according to claim 8,
wherein one of the anode line and the cathode line is configured to
surround the peripheral area, and the anode line and the cathode
line are configured to receive voltages from the same edge of the
peripheral area.
14. The organic light emitting display device according to claim 8,
further comprising: a jump line, wherein the anode line and the
cathode line are formed of the same material, one of the anode line
and the cathode line is divided into at least two parts in the
peripheral area, and the line divided into at least two parts is
connected by the jump line.
15. The organic light emitting display device according to claim 8,
wherein the cathode line includes at least two metal layers, and at
least the two metal layers are connected with each other through a
contact hole.
16. The organic light emitting display device according to claim 8,
wherein the plurality of sub-pixels include an anode and a cathode,
and wherein in each of the plurality of sub-pixels, the cathode
line and the anode line are interdigitated to reduce a deviation in
a potential difference between the anode and the cathode.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of Korean Patent
Application No. 10-2014-0196003 filed on Dec. 31, 2014, and Korean
Patent Application No. 10-2015-0061775 filed on Apr. 30, 2015 in
the Korean Intellectual Property Office, which are all incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present disclosure relates to an organic light emitting
display device, and more particularly, to an organic light emitting
display device including a voltage supply line structure which can
improve luminance uniformity of the organic light emitting display
device by reducing a deviation in a potential difference between an
anode and a cathode depending on a position of an active area of
the organic light emitting display device when the organic light
emitting display device is enlarged.
[0004] 2. Description of the Related Art
[0005] As the age of information technology has proceeded, the
field of display devices for visually displaying electrical
information signals has grown rapidly. Thus, studies for developing
technologies, such as thinning, weight lightening, and low power
consumption, of various flat panel display devices have continued.
Representative examples of the flat panel display devices include a
Liquid Crystal Display (LCD) device, a Plasma Display Panel (PDP)
device, a Field Emission Display (FED) device, an Electro-Wetting
Display (EWD) device, an Organic Light Emitting Display (OLED)
device, and the like.
[0006] An organic light emitting display device is a self-light
emitting display device that does not need a separate light source
unlike a liquid crystal display, and thus, the organic light
emitting display device can be manufactured in a lightweight and
thin form. Further, the OLED is advantageous in terms of power
consumption since it is driven with a low voltage. Also, the
organic light emitting display device has excellent color
expression ability, a high response speed, a wide viewing angle,
and a high contrast ratio (CR). Therefore, the OLED has attracted
attention as a next-generation display device.
[0007] An active area (AA) of the organic light emitting display
device includes a plurality of sub-pixels. Each of the sub-pixels
includes an organic light emitting diode (OELD). Each organic light
emitting diode includes an anode, an organic light emitting layer,
and a cathode. An anode voltage ELVDD is supplied to the anode, and
a cathode voltage ELVSS is supplied to the cathode.
[0008] If the organic light emitting display device is of a
top-emission type, the cathode uses a transparent or translucent
electrode in order to upwardly emit light emitted from the organic
light emitting layer. The cathode is formed to have small thickness
in order to secure transparency. Therefore, resistance of the
cathode becomes very high.
[0009] In order to secure the reliability of the display device, an
encapsulation part configured to protect the organic light emitting
layer against moisture, a physical shock, or impurities which may
be generated during a manufacturing process is formed on an organic
light emitting element including the organic light emitting layer.
In the top-emission organic light emitting display device, a glass
encapsulation part, or an encapsulation part having a thin film
encapsulation structure in which an inorganic encapsulation layer
and an organic layer for delaying infiltration of moisture is used
as the encapsulation part.
[0010] As a size of the top-emission organic light emitting display
device is increased, a length of a line for supplying a voltage is
also increased. Aline resistance applied to each of the sub-pixels
is increased in proportion to the length of the line. Therefore,
there is a difference in voltage transmitted along the line for
each sub-pixel. Accordingly, luminance uniformity of the organic
light emitting display device is decreased.
SUMMARY OF THE INVENTION
[0011] In recent years, a high-density and high-resolution organic
light emitting display device has been demanded. Further, various
compensation circuits to be added to an active area have been
demanded in order to improve an image quality of an organic light
emitting display device. Therefore, when an anode line for
supplying an anode voltage ELVDD and a cathode line for supplying a
cathode voltage ELVSS are disposed in an organic light emitting
display device, it is difficult to secure a sufficient width for
line.
[0012] The inventors of the present disclosure have continued
various studies for improving a decrease in image luminance
uniformity which worsens as a top-emission organic light emitting
display device is increased in size. To be specific, the inventors
have continued on research and development of a disposition
structure of a cathode line and an anode line for reducing a
problem of a line resistance.
[0013] To be specific, the inventors have studied a new disposition
structure of voltage supply lines capable of improving uniformity
in a potential difference between an anode and a cathode applied to
each sub-pixel even if voltage is decreased due to a line
resistance.
[0014] In particular, the inventors noted the fact that an anode
voltage ELVDD is gradually decreased as a length of a line from a
voltage supply source is increased, whereas a cathode voltage ELVSS
is gradually increased as a length of a line from a voltage supply
source is increased.
[0015] The inventors of the present disclosure invented an organic
light emitting display device capable of uniformly improving a
potential difference between an anode and a cathode by optimizing
an input direction of an anode voltage ELVDD supply line and an
input direction of a cathode voltage ELVSS supply line.
[0016] Thus, an object of the present disclosure is to provide an
organic light emitting display device which can be uniformity
improved in a potential difference between an anode and a cathode
by providing a voltage supply line structure which has a uniform
line resistance regardless of a position of a sub-pixel since an
input direction of an anode line for supplying an anode voltage
ELVDD and an input direction of a cathode line for supplying a
cathode voltage ELVSS are opposite to each other.
[0017] Another object of the present disclosure is to provide an
organic light emitting display device including a voltage supply
line and a voltage supply pad which can be applied to an organic
light emitting display device having light transparency by
optimizing a voltage supply line structure.
[0018] The objects of the present disclosure are not limited to the
aforementioned objects, and other objects, which are not mentioned
above, will be apparent to a person having ordinary skill in the
art from the following description.
[0019] Yet another object of the present invention is to provide an
organic light emitting display device including sub-pixel
structures respectively optimized for the above-described voltage
supply line structures, and an image signal compensation unit
corresponding to the sub-pixel structures.
[0020] Still another object of the present invention is to provide
an organic light emitting display device including a transmission
unit having light transparency optimized for the above-described
sub-pixel structures.
[0021] According to an aspect of the present disclosure, there is
provided an organic light emitting display device. The organic
light emitting display device includes: a plurality of sub-pixels
including an anode and a cathode; an anode line configured to
supply an anode voltage to the anode; and a cathode line configured
to supply a cathode voltage to the cathode, and in each of the
plurality of sub-pixels, a direction of an anode voltage input of
the anode line and a direction of a cathode voltage input of the
cathode line are different from each other and face each other in
order to reduce a deviation in a potential difference between the
anode and the cathode. Thus, it is possible to improve uniformity
in the potential difference between the anode and the cathode
caused by a line resistance.
[0022] According to another feature of the present disclosure, the
organic light emitting display device is configured such that the
anode voltage in the anode line is gradually decreased along the
direction of the anode voltage input, the organic light emitting
display device is configured such that the cathode voltage in the
cathode line is gradually increased along the direction of the
cathode voltage input, and a degree of decrease in the anode
voltage in the anode line according to a distance and a degree of
increase in the cathode voltage in the cathode line according to a
distance is set by a line resistance of the anode line and the
cathode line, respectively.
[0023] According to yet another feature of the present disclosure,
the organic light emitting display device is configured to resolve
the problem of the deviation in the potential difference between
the anode and the cathode in the plurality of sub-pixels by
offsetting the increased cathode voltage in the cathode line by the
decreased anode voltage in the anode line.
[0024] According to still another feature of the present
disclosure, the line resistance of the anode line and the line
resistance of the cathode line have a difference of less than
10%.
[0025] According to still another feature of the present
disclosure, the organic light emitting display device further
includes: an active area including the plurality of sub-pixels; and
a peripheral area configured to surround the active area, where the
anode line is extended from an edge of the peripheral area to the
other edge facing the edge so as to be connected with the plurality
of sub-pixels, and the cathode line is extended from the other edge
of the peripheral area to the edge facing the other edge so as to
be connected with the plurality of sub-pixels.
[0026] According to still another feature of the present
disclosure, the anode line and the cathode line include one-way
input lines, and the anode line and the cathode line are
short-circuited at a dead-end of the active area.
[0027] According to still another feature of the present
disclosure, the anode line and the cathode line are formed in a
comb shape, and the anode line and the cathode line are configured
such that comb teeth line segments are disposed to cross each other
in the active area.
[0028] According to another aspect of the present disclosure, there
is provided an organic light emitting display device. The organic
light emitting display device includes: an active area including a
plurality of sub-pixels; a peripheral area configured to surround
the active area; an anode line disposed from a first edge of the
peripheral area and extended towards a second edge opposing the
first edge so as to supply an anode voltage from the first edge of
the peripheral area towards the second edge to the active area; and
a cathode line disposed from the second edge of the peripheral area
and extended towards the first edge so as to supply a cathode
voltage from the second edge of the peripheral area towards the
first edge to the active area. Thus, it is possible to improve
uniformity in a potential difference between an anode and a cathode
caused by a line resistance.
[0029] According to another feature of the present disclosure, each
of the plurality of sub-pixels includes: a driving transistor
including an active layer, a gate electrode, a source electrode,
and a drain electrode; a data line configured to apply an image
signal to the driving transistor; and an organic light emitting
diode driven by the driving transistor including an anode, an
organic light emitting layer, and a cathode, and the data line is
electrically connected with the gate electrode of the driving
transistor, where the anode line is electrically connected with the
drain electrode of the driving transistor, and the cathode line is
electrically connected with the cathode of the organic light
emitting diode.
[0030] According to yet another feature of the present disclosure,
the image signal applied to the driving transistor through the data
line is an image signal modified to compensate a voltage Vgs
according to an increment in cathode voltage in the cathode of each
of the plurality of sub-pixels.
[0031] According to yet another feature of the present disclosure,
the image signal may be compensated proportionally to the increment
in the cathode voltage.
[0032] According to still another feature of the present
disclosure, the plurality of sub-pixels further include a light
transmission part for providing light transparency.
[0033] According to still another feature of the present
disclosure, the organic light emitting display device further
includes: at least one circuit board, where at least one circuit
board is disposed so as not to be overlapped with a rear surface of
the active area.
[0034] According to still another feature of the present
disclosure, one of the anode line and the cathode line is
configured to surround the peripheral area, and the anode line and
the cathode line are configured to receive voltages from the same
edge of the peripheral area.
[0035] According to still another feature of the present
disclosure, the organic light emitting display device further
includes: a jump line, and the anode line and the cathode line are
formed of the same material. One of the anode line and the cathode
line is divided into at least two parts in the peripheral area, and
the line divided into at least two parts is connected by the jump
line.
[0036] According to still another feature of the present
disclosure, the cathode line includes at least two metal layers,
and at least the two metal layers are connected with each other
through a contact hole.
[0037] Details of other example embodiments will be included in the
detailed description of the invention and the accompanying
drawings.
[0038] The present disclosure has an effect of improving luminance
uniformity of an organic light emitting display device since an
input direction of an anode line for supplying an anode voltage
ELVDD and an input direction of a cathode line for supplying a
cathode voltage ELVSS are opposite to each other.
[0039] Further, the present disclosure has an effect of improving
luminance uniformity of an organic light emitting display device
since a unit line resistance of an anode line and a unit line
resistance of a cathode line are set to be substantially equal to
each other.
[0040] Furthermore, the present disclosure has an effect of
providing a voltage supply line structure which can be applied to
an organic light emitting display device having light transparency
since various circuit boards are disposed only at a first side
surface of a peripheral area of an organic light emitting display
panel and a single voltage supply line is extended from the first
side surface to a third side surface through the peripheral
area.
[0041] Also, the present disclosure has an effect of further
improving luminance uniformity with the image signal compensation
unit.
[0042] The effects of the present disclosure are not limited to the
aforementioned effects, and other various effects are included in
the present specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The above and other aspects, features and other advantages
of the present disclosure will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0044] FIG. 1A is a schematic plan view of an organic light
emitting display device according to an example embodiment of the
present disclosure;
[0045] FIG. 1B is a schematic plan view provided to describe
disposition positions of circuit boards at a rear surface of the
organic light emitting display device according to the example
embodiment of the present disclosure;
[0046] FIG. 1C is a schematic cross-sectional view of a sub-pixel
of the organic light emitting display device according to the
example embodiment of the present disclosure;
[0047] FIG. 1D is a schematic equivalent circuit diagram provided
to describe a resistance value of each sub-pixel in the organic
light emitting display device according to the example embodiment
of the present disclosure;
[0048] FIG. 1E is a schematic graph provided to describe a
potential difference between an anode and a cathode of each
sub-pixel in the organic light emitting display device according to
the example embodiment of the present disclosure;
[0049] FIG. 1F is a schematic equivalent circuit diagram provided
to describe a resistance value of each sub-pixel in an organic
light emitting display device according to Comparative Example
1;
[0050] FIG. 1G is a schematic graph provided to describe a
potential difference between an anode and a cathode of each
sub-pixel in the organic light emitting display device according to
Comparative Example 1;
[0051] FIG. 1H is a schematic equivalent circuit diagram provided
to describe a resistance value of each sub-pixel in an organic
light emitting display device according to Comparative Example
2;
[0052] FIG. 1I is a schematic graph provided to describe a
potential difference between an anode and a cathode of each
sub-pixel in the organic light emitting display device according to
Comparative Example 2;
[0053] FIG. 2 is a schematic plan view of an organic light emitting
display device according to another example embodiment of the
present disclosure;
[0054] FIG. 3 is a schematic plan view of an organic light emitting
display device according to yet another example embodiment of the
present disclosure;
[0055] FIG. 4A is a schematic plan view of an organic light
emitting display device according to still another example
embodiment of the present disclosure; and
[0056] FIG. 4B is a schematic cross-sectional view of a sub-pixel
of the organic light emitting display device according to still
another example embodiment of the present disclosure illustrated in
FIG. 4A.
[0057] FIG. 5A is a schematic plan view of an organic light
emitting display device including an image signal compensation unit
according to still another example embodiment of the present
disclosure;
[0058] FIG. 5B is a schematic equivalent circuit diagram provided
to describe a resistance value of each sub-pixel in an organic
light emitting display device to which a compensated image signal
is supplied according to still another example embodiment of the
present disclosure;
[0059] FIG. 5C is a schematic graph provided to describe a
potential difference between anode and cathode of each sub-pixel,
and a compensated image signal in the organic light emitting
display device according to still another example embodiment of the
present disclosure;
[0060] FIG. 6A is a schematic plan view of an organic light
emitting display device including a data driver IC according to
still another example embodiment of the present disclosure;
[0061] FIG. 6B is a schematic equivalent circuit diagram provided
to describe a resistance value of each modified sub-pixel in an
organic light emitting display device to which a compensated image
signal is supplied according to still another example embodiment of
the present disclosure; and
[0062] FIG. 6C is a schematic graph provided to describe a
potential difference between anode and cathode of each modified
sub-pixel, and a compensated image signal in the organic light
emitting display device according to still another example
embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0063] Advantages and features of the present disclosure, and
methods for accomplishing the same will be more clearly understood
from example embodiments described below with reference to the
accompanying drawings. However, the present disclosure is not
limited to the following example embodiments but may be implemented
in various different forms. The example embodiments are provided
only to complete disclosure of the present disclosure and to fully
provide a person having ordinary skill in the art to which the
present disclosure pertains with the category of the invention, and
the present disclosure will be defined by the appended claims.
[0064] The shapes, sizes, ratios, angles, numbers, and the like
illustrated in the accompanying drawings for describing the example
embodiments of the present disclosure are merely examples, and the
present disclosure is not limited thereto. Like reference numerals
generally denote like elements throughout the present
specification. Further, in the following description, a detailed
explanation of known related technologies may be omitted to avoid
unnecessarily obscuring the subject matter of the present
disclosure. The terms such as "including," "having," and "consist
of" used herein are generally intended to allow other components to
be added unless the terms are used with the term "only". Any
references to singular may include plural unless expressly stated
otherwise.
[0065] Components are interpreted to include an ordinary error
range even if not expressly stated.
[0066] When the position relation between two parts is described
using the terms such as "on", "above", "below", and "next", one or
more parts may be positioned between the two parts unless the terms
are used with the term "immediately" or "directly".
[0067] When an element or layer is referred to as being "on"
another element or layer, it may be directly on the other element
or layer, or intervening elements or layers may be present.
[0068] Although the terms "first", "second", and the like are used
for describing various components, these components are not
confined by these terms. These terms are merely used for
distinguishing one component from the other components. Therefore,
a first component to be mentioned below may be a second component
in a technical concept of the present disclosure.
[0069] Throughout the whole specification, the same reference
numerals denote the same elements.
[0070] Since size and thickness of each component illustrated in
the drawings are represented for convenience in explanation, the
present disclosure is not necessarily limited to the illustrated
size and thickness of each component.
[0071] The features of various embodiments of the present
disclosure can be partially or entirely bonded to or combined with
each other and can be interlocked and operated in technically
various ways as can be fully understood by a person having ordinary
skill in the art, and the embodiments can be carried out
independently of or in association with each other.
[0072] Various example embodiments of the present disclosure will
be described in detail with reference to the accompanying
drawings.
[0073] FIG. 1A and FIG. 1B are schematic plan views of an organic
light emitting display device according to an example embodiment of
the present disclosure.
[0074] Referring to FIG. 1A and FIG. 1B, an organic light emitting
display device 100 according to an example embodiment of the
present disclosure includes an organic light emitting display panel
110, a data circuit board 140, a control circuit board 142, a first
flexible circuit board 144, a second flexible circuit board 146,
and a flexible cable 148.
[0075] The control circuit board 142 is electrically connected with
the data circuit board 140 by the flexible cable 148. The data
circuit board 140 is electrically connected with the organic light
emitting display panel 110 through the first flexible circuit board
144 and the second flexible circuit board 146.
[0076] 1. Organic Light Emitting Display Panel
[0077] The organic light emitting display panel 110 includes an
active area AA and a peripheral area PA. In the active area AA of
the organic light emitting display panel 110, a plurality of
sub-pixels 112 including a white sub-pixel, a red sub-pixel, a
green sub-pixel, and a blue sub-pixel, a plurality of gate lines
116, a plurality of data lines 120, a plurality of second anode
lines 130b, and a plurality of second cathode lines 134b are
disposed, so that the active area AA is configured to display an
image. The peripheral area PA of the organic light emitting display
panel 110 is configured to surround the active area AA. In the
peripheral area PA, various lines and circuits are disposed to
drive the plurality of sub-pixels 112 of the active area AA. In the
peripheral area PA, a first anode line 130a, a first cathode line
134a, and a plurality of pads are disposed, and additional circuit
components can be further disposed. For example, a flexible printed
circuit board (FPCB), a flexible cable, a semiconductor chip, or
the like may be bonded on the plurality of pads by a bonding
member. Examples of the lines which can be connected with the
plurality of pads may include the plurality of gate lines 116, the
plurality of data lines 120, the first anode line 130a, the first
cathode line 134a, and the like.
[0078] 2. Control Circuit Board
[0079] The control circuit board 142 performs a function of
receiving a digital image signal, various reference voltages, and
various control signals from an external system and controlling the
organic light emitting display panel 110 to display an image on the
organic light emitting display panel 110. In order to perform the
above-described function, the control circuit board 142 may have a
configuration in which circuit components such as a processor, a
memory, a look-up table, a buffer, a gamma control circuit, an LVDS
(low voltage differential signal) line, a connector, and a power
control unit are disposed on a printed circuit board (PCB), but may
not be limited thereto.
[0080] The control circuit board 142 precisely controls the image
signal, a time interval and a frequency cycle of the control
signals and the like so as to display the digital image signal on
the organic light emitting display panel 110. In the circuit
components disposed on the control circuit board 142, various image
processing algorithms and the like for having various image
qualities or low power consumption can be implemented.
[0081] A digital image signal input to the control circuit board
142 from the external system is an image signal including three RGB
(red, green, blue) primary colors. The organic light emitting
display panel 110 according to the example embodiment of the
present disclosure includes the white, red, green, and blue
sub-pixels 112, and thus, in the circuit components disposed on the
control circuit board 142, a rendering algorithm capable of
converting a RGB image signal into a WRGB (white, red, green, blue)
image signal can be implemented.
[0082] A digital image signal output from the control circuit board
142 is a WRGB image signal, but may not be limited thereto.
However, for convenience in explanation, only a control signal
related to the present disclosure among various control signals
described above will be described later in detail.
[0083] Various reference voltages output from the control circuit
board 142 may include an anode voltage ELVDD, a cathode voltage
ELVSS, a gamma reference voltage, an initial voltage (Vinit), a
gate high voltage (VGH), a gate low voltage (VGL), an external
compensation reference voltage (Vref), and the like, but may not be
limited thereto. However, for convenience in explanation, only a
reference voltage related to the present disclosure among various
reference voltages described above will be described later in
detail.
[0084] The anode voltage ELVDD refers to a voltage applied to an
anode electrode in the active area AA of the organic light emitting
display panel 110. The cathode voltage ELVSS refers to a voltage
applied to a cathode electrode in the active area AA of the organic
light emitting display panel 110. The gamma reference voltage is
used when a digital image signal is converted into an analogue
image signal in a data driver IC 118. The initial voltage
suppresses distortion of a black scale of an image by discharging
an image signal of a previous image frame that was stored in a
capacitor of the sub-pixel 112 in the active area AA. The gate high
voltage and the gate low voltage switches a gate driver IC on and
off. The external compensation reference voltage compensates a
threshold-voltage (Vth) difference of a driving transistor D.sub.TR
of the sub-pixel 112.
[0085] Among the above-described reference voltages, the anode
voltage ELVDD, the cathode voltage ELVSS, and the gamma reference
voltage are important reference voltages which may directly affect
an image quality of the organic light emitting display panel 110
and thus need to be uniformly and stably supplied to the organic
light emitting display panel. However, this should not be construed
that the other voltages do not directly affect an image
quality.
[0086] Various control signals output from the control circuit
board 142 may include a gate start pulse (GSP), a gate out enable
(GOE), a dot clock, and the like, but may not be limited thereto.
However, for convenience in explanation, only a control signal
related to the present disclosure among the various control signals
described above will be described later in detail.
[0087] In some example embodiments, the organic light emitting
display panel may include red, green, blue, and green sub-pixels.
Therefore, in the circuit components disposed on the control
circuit board, a rendering algorithm capable of converting a RGB
image signal into a RGBG (red, green, blue, green) image signal can
be implemented.
[0088] In some example embodiments, the organic light emitting
display panel may include red, green, blue, and yellow sub-pixels.
Therefore, in the circuit components disposed on the control
circuit board, a rendering algorithm capable of converting a RGB
image signal into a RGBY (red, green, blue, yellow) image signal
can be implemented.
[0089] In some example embodiments, the organic light emitting
display panel may include red, green, and blue sub-pixels.
[0090] 3. Flexible Cable
[0091] The flexible cable 148 electrically connects the control
circuit board 142 with the data circuit board 140. The flexible
cable 148 transfers the digital image signal, various reference
voltages, and various control signals output from the control
circuit board 142 to the data circuit board 140. One side of the
flexible cable 148 is connected with a connector disposed on the
control circuit board 142, and the other side thereof is connected
with a connector disposed on the data circuit board 140. However,
the flexible cable and the connectors are just means for electrical
connection, but the present disclosure may not be limited
thereto.
[0092] Referring to FIG. 1A and FIG. 1B, four connectors are
disposed on the control circuit board 142, and each of the
connectors is connected with each flexible cable 148. According to
this configuration, the control circuit board 142 may supply
various signals to an upper side surface (first side surface) and a
lower side surface (third side surface) of the organic light
emitting display panel 110 on the basis of a Y-axis.
[0093] Herein, the first side surface may be defined as the upper
side surface, a second side surface may be defined as a left side
surface, the third side surface may be defined as the lower side
surface, and a fourth side surface may be defined as a right side
surface.
[0094] 4. Data Circuit Board
[0095] The data circuit board 140 receives the digital image
signal, various reference voltages, and various control signals
output from the control circuit board 142 and transfers the
above-described signals and voltages to the organic light emitting
display panel 110 through the first flexible circuit board 144 and
the second flexible circuit board 146. In order to perform the
above-described function, the data circuit board 140 includes
various circuit components disposed on a printed circuit board
(PCB). For example, the data circuit board 140 may be configured to
include passive components such as a resistor and a capacitor in
order to stabilize a gamma reference voltage which becomes a basis
for generating an analogue image signal of the data driver IC 118.
Further, the data circuit board 140 may be configured such that a
line resistance of the data circuit board 140 is minimized in order
to minimize a voltage drop of an anode voltage ELVDD, a cathode
voltage ELVSS, and a gamma reference voltage.
[0096] Referring to FIG. 1A and FIG. 1B, the data circuit board 140
disposed on the lower side surface (or third side surface) of the
organic light emitting display panel 110 in a direction of a Y-axis
does not include the data driver IC 118, and thus, does not include
any passive component for stabilizing a gamma reference
voltage.
[0097] In some example embodiments, the control circuit board and
the data circuit board may be combined into a single circuit board.
In this case, the flexible cable is not needed and thus may be
removed.
[0098] 5. Data Driver IC
[0099] The data driver IC 118 serves as a DAC (digital to analogue
converter) that converts a digital image signal into an analogue
image signal so as to supply the analogue image signal to the data
line 120 in the active area AA of the organic light emitting
display panel 110 connected with the data driver IC 118. The data
driver IC 118 is formed of a semiconductor chip and bonded on the
first flexible circuit board 144 by a bonding member according to a
COF (chip on film) bonding method. The data driver IC 118 in the
form of a semiconductor chip has a predetermined number of
controllable data lines or channels, and the number of data driver
ICs 118 may be determined by the number of the data lines 120 of
the organic light emitting display panel 110 and the number of the
channels of the data driver IC 118. However, the number of data
driver ICs 118 may not be limited thereto.
[0100] The data driver IC 118 converts a digital image signal
transferred from the control circuit board 142 into an analogue
image signal using a gamma reference voltage in order to display a
gray scale of an image signal on the sub-pixel 112. The data driver
IC 118 is supplied with the gamma reference voltage from the data
circuit board 140. The analogue image signal is generated using the
gamma reference voltage. Preferably, the image signal has a gamma
curve with a gamma value of 2.2, but may not be limited
thereto.
[0101] The sub-pixel 112 includes red, green, and blue color
filters and an organic light emitting layer that emits a white
light. In particular, according to this configuration, organic
light emitting layers are the same regardless of a color of a
sub-pixel, and thus, the sub-pixel 112 may be configured such that
gamma curves for the respective colors are the same, but may not be
limited thereto. The sub-pixel 112 may be configured to have an
independent gamma curve for each color.
[0102] An anisotropic conductive film (ACF) is used as the bonding
member. In particular, as the organic light emitting display panel
110 is vulnerable to high temperature, it is difficult to perform
typical soldering thereto. Thus, it is desirable to use an
anisotropic conductive film. In the anisotropic conductive film,
conductive particles are dispersed, and bonded to each other by
heat and pressure. Herein, a film layer of the anisotropic
conductive film retains an adhesive strength between the plurality
of pads and the semiconductor chip, and the dispersed conductive
particles electrically connect the plurality of pads with the
semiconductor chip at a bonding area. However, the bonding member
may not be limited thereto.
[0103] In some example embodiments, the plurality of sub-pixels of
the organic light emitting display panel may be formed to include
red, green, and blue organic light emitting layers configured to
emit red, green, and blue lights, respectively. Herein, color
filters can be removed. If the organic light emitting layers are
different from each other, electrical characteristics of the
organic light emitting layers are different from each other. Thus,
a gamma voltage needs to be set differently for each color of each
sub-pixel.
[0104] 6. First Flexible Circuit Board
[0105] The first flexible circuit board 144 includes the data
driver IC 118 and electrically connects the data circuit board 140
with the organic light emitting display panel 110. One side surface
of the first flexible circuit board 144 is bonded to the organic
light emitting display panel 110, and the other side thereof is
bonded to one side of the data circuit board 140. The data driver
IC 118 is bonded to a central area of the first flexible circuit
board 144. The first flexible circuit board 144 includes a
plurality of pads on the one side surface, a plurality of pads on
the other side surface, and a plurality of pads on the central
area. That is, the first flexible circuit board 144 has a COF (chip
on film) shape in which a semiconductor chip is disposed on a film.
A bonding member is disposed on the plurality of pads. As the
bonding member, an anisotropic conductive film is used. However,
the bonding member may not be limited thereto.
[0106] 7. Second Flexible Circuit Board
[0107] The second flexible circuit board 146 electrically connects
the data circuit board 140 with the organic light emitting display
panel 110, and supplies at least one reference voltage to the
organic light emitting display panel 110. One side surface of the
second flexible circuit board 146 is bonded to the organic light
emitting display panel 110, and the other side surface thereof is
bonded to one side surface of the data circuit board 140. The
second flexible circuit board 146 includes a plurality of pads on
the one side surface and a plurality of pads on the other side
surface. That is, the second flexible circuit board 146 has a FOG
(film on glass) shape in which electric lines are formed on a film.
A bonding member is disposed on the plurality of pads. As the
bonding member, an anisotropic conductive film is used. However,
the bonding member may not be limited thereto.
[0108] To be specific, the second flexible circuit board 146
receives an anode voltage ELVDD or a cathode voltage ELVSS from the
data circuit board 140 and supplies the voltage to the plurality of
sub-pixels 112 disposed in the active area AA of the organic light
emitting display panel 110.
[0109] In order to improve luminance uniformity of the organic
light emitting display panel 110, the anode voltage ELVDD and the
cathode voltage ELVSS need to be stable. Therefore, in order to
minimize a line resistance of a voltage supply line of the second
flexible circuit board 146, the voltage supply line is formed to
have a total width that is sufficiently large. Herein, the voltage
supply line may be implemented as being divided into a plurality of
narrow lines. If a line resistance is high and a potential
difference between the anode voltage ELVDD and the cathode voltage
ELVSS is not uniform in the active area AA, brightness of an image
displayed on the organic light emitting display panel 110 is
different in each active area AA. In order to solve this problem, a
plurality of second flexible circuit boards 146 may be disposed in
the peripheral area PA of the organic light emitting display panel
110. Herein, preferably, the second flexible circuit boards 146 may
be separated from each other by a predetermined gap. According to
the above-described configuration, it is possible to distribute a
current capacity which can flow through each flexible circuit
board, and thus, there is an advantage of reducing heat generation
or burning caused by an overcurrent.
[0110] In some example embodiments, the data driver IC may be
bonded on a plurality of pads disposed in the peripheral area PA of
the organic light emitting display panel according to a COG (chip
on glass) bonding method. Herein, the first flexible circuit board
does not include a plurality of pads on the central area and
electrically connects the data circuit board with the organic light
emitting display panel and transfers an image signal transferred
from the data circuit board to the data driver IC. If the data
driver IC is disposed in a COG (chip on glass) shape, the data
driver IC does not need to be disposed on the first flexible
circuit board. Thus, the first flexible circuit board may have a
FOG shape.
[0111] In some example embodiments, both of the first flexible
circuit substrate and the second flexible circuit substrate may be
configured to receive an anode voltage ELVDD and a cathode voltage
ELVSS from the data circuit board. Herein, the first flexible
circuit board includes the data driver IC. If both of the first
flexible circuit substrate and the second flexible circuit
substrate are configured to receive an anode voltage ELVDD and a
cathode voltage ELVSS, it is possible to more uniformly distribute
a current capacity which can flow through each flexible circuit
board, and thus, there is an advantage of further reducing heat
generation or burning caused by an overcurrent.
[0112] In some example embodiments, the first flexible circuit
substrate and the second flexible circuit substrate may be
alternately disposed along the upper side surface (first side
surface) of the organic light emitting display panel 110. The
alternately disposed flexible circuit boards can alleviate a
problem of an overcurrent flowing to a specific flexible circuit
board.
[0113] In some example embodiments, a combined flexible circuit
board in which the first flexible circuit substrate and the second
flexible circuit substrate are combined may be disposed. That is,
the first flexible circuit substrate and the second flexible
circuit substrate can be combined or separated in various forms if
necessary.
[0114] 8. Gate Driver IC
[0115] Agate driver IC 114 supplies a gate line driving signal to
the plurality of gate lines 116 connected to the plurality of
sub-pixels 112 of the organic light emitting display panel 110. The
control circuit board 142 generates a driving signal for driving
the gate driver IC 114 and supplies the driving signal to the gate
driver IC 114. The gate driver IC 114 is disposed in the peripheral
area PA of the organic light emitting display panel 110. To be
specific, the gate driver IC 114 is disposed on both side surfaces
(the second side surface and the fourth side surface) of the
organic light emitting display panel 110. In particular, according
to this configuration, both side surfaces (the second side surface
and the fourth side surface) can apply gate line driving signals,
and thus, there is an effect of alleviating a decrease in quality
of a gate line driving signal in a large organic light emitting
display panel in which the gate lines 116 are increased in
length.
[0116] The gate driver IC 114 is formed of a semiconductor chip and
bonded on the plurality of pads disposed in the peripheral area PA
of the organic light emitting display panel 110 by a COG (chip on
glass) bonding method. The gate driver IC 114 in the form of a
semiconductor chip has a predetermined number of controllable gate
lines or channels, and the number of gate driver ICs 114 may be
determined by the number of the gate lines 116 of the organic light
emitting display panel 110 and the number of the channels of the
gate driver IC 114. However, the number of gate driver ICs 114 may
not be limited thereto. An anisotropic conductive film may be used
as a bonding member. However, the bonding member may not be limited
thereto.
[0117] 9. Sub-Pixel
[0118] Referring to FIG. 1C, the sub-pixel 112 in the active area
AA includes at least a first substrate 160, a driving transistor
162 disposed on the first substrate 160, an organic light emitting
diode 164 driven by the driving transistor 162, the second anode
line 130b, and the second cathode line 134b.
[0119] The first substrate 160 is formed of a material suitable for
deposition of a semiconductor layer, a metal layer, an organic thin
film, an inorganic thin film, or the like. For example, glass or
plastic such as polyimide having excellent thermal and chemical
resistance may be applied to the first substrate 160.
[0120] The driving transistor 162 according to an example
embodiment of the present disclosure has an N-type structure. The
driving transistor 162 according to an example embodiment of the
present disclosure has a coplanar structure.
[0121] The driving transistor 162 includes an active layer 168, a
gate electrode 170, a source electrode 172, and a drain electrode
174.
[0122] The active layer 168 is disposed on the first substrate 160.
The active layer 168 is formed of a material having a semiconductor
characteristic. For example, amorphous silicon, low-temperature
polysilicon, an oxide substance, an organic substance, or the like
may be applied to the active layer 168. However, the present
disclosure may not be limited thereto.
[0123] A gate insulating film 176 is disposed on the active layer
168. The gate insulating film 176 is configured to cover the active
layer 168. The gate insulating film 176 is formed of an inorganic
substance. For example, silicon oxide (SiOx), silicon nitride
(SiNx), aluminum oxide (Al.sub.2O.sub.3), or the like may be
applied to the gate insulating film 176. However, the present
disclosure may not be limited thereto.
[0124] The gate electrode 170 is disposed on the gate insulating
film 176. Further, the gate electrode 170 is configured to be
overlapped with at least a partial area of the active layer 168.
The gate electrode 170 is formed of metal. The gate electrode 170
may be formed of the same material as that of the gate lines 116.
For example, copper (Cu), aluminum (Al), silver (Ag), molybdenum
(Mo), titanium (Ti), gold (Au), transparent conductive oxide (TCO),
laminates thereof, or the like may be applied to the gate electrode
170. However, the present disclosure may not be limited
thereto.
[0125] An interlayer insulating film 178 is disposed on the gate
electrode 170. The interlayer insulating film 178 is configured to
cover the gate electrode 170. The interlayer insulating film 178 is
formed of an inorganic substance. For example, silicon oxide,
silicon nitride, aluminum oxide, or the like may be applied to the
interlayer insulating film 178. Otherwise, the interlayer
insulating film 178 may have a double-layer structure formed of
silicon oxide and silicon nitride. However, the present disclosure
may not be limited thereto.
[0126] The source electrode 172 and the drain electrode 174 are
disposed on the interlayer insulating film 178. The source
electrode 172 and the drain electrode 174 are configured to be
electrically connected with the active layer 168. To be specific,
the source electrode 172 is connected with one end of the active
layer 168 through a first contact hole 178a penetrating the gate
insulating film 176 and the interlayer insulating film 178.
Further, the drain electrode 174 is connected with the other end of
the active layer 168 through the first contact hole 178a
penetrating the gate insulating film 176 and the interlayer
insulating film 178. The source electrode 172 and the drain
electrode 174 are formed of metal. The source electrode 172 and the
drain electrode 174 may be formed of the same material as that of
the data lines 120. For example, copper (Cu), aluminum (Al), silver
(Ag), molybdenum (Mo), titanium (Ti), gold (Au), transparent
conductive oxide (TCO), laminates thereof, or the like may be
applied to the source electrode 172 and the drain electrode 174.
However, the present disclosure may not be limited thereto.
[0127] The second anode line 130b is disposed on the interlayer
insulating film 178. The second anode line 130b supplies an anode
voltage ELVDD to the active area AA. To be specific, the second
anode line 130b is configured to be electrically connected with the
drain electrode 174 of the driving transistor 162. The second anode
line 130b is electrically connected with the first anode line 130a
disposed in the peripheral area PA, thereby constituting an anode
line 130. According to the above-described configuration, the anode
voltage ELVDD is supplied to the driving transistor 162 through the
anode line 130. The second anode line 130b may be formed of the
same material as that of the data lines 120. However, the present
disclosure may not be limited thereto.
[0128] A transistor insulating film 180 is disposed on the driving
transistor 162. The transistor insulating film 180 is formed of an
inorganic substance. For example, silicon oxide, silicon nitride,
aluminum oxide, or the like may be applied to the transistor
insulating film 180. However, the present disclosure may not be
limited thereto. The transistor insulating film 180 may
additionally suppress infiltration of moisture into the driving
transistor 162.
[0129] An organic layer 182 is disposed on the transistor
insulating film 180. The organic layer 182 is formed of an organic
substance having a low permittivity (0. Therefore, the organic
layer 182 can reduce a parasitic capacitance generated between an
anode 184 and the driving transistor 162 and between the gate line
116 and a data line 115. For example, photo acryl and the like may
be applied to the organic layer 182. However, the present
disclosure may not be limited thereto. Further, the organic layer
182 may planarize step portions formed by various components of the
driving transistor 162.
[0130] The organic light emitting diode 164 includes the anode 184,
a cathode 190, and an organic light emitting layer 188 interposed
therebetween. A light emitting area of the organic light emitting
layer 188 may be defined by a bank 186.
[0131] The anode 184 is disposed on the organic layer 182. The
anode 184 is configured to correspond to a light emitting area of
each sub-pixel 112. A second contact hole 182a is configured to
penetrate the organic layer 182 and the transistor insulating film
180. Therefore, the anode 184 is connected with the source
electrode 172 of the driving transistor 162 through the second
contact hole 182a. The anode 184 is formed of a material having a
high work function. The anode 184 may be formed of a reflective
material so as to have reflectivity, or may include a reflective
plate at a lower part thereof.
[0132] The anode 184 including a reflective plate will be described
for convenience in explanation. The reflective plate is formed of a
metallic material having a high reflectivity to visible light. For
example, silver (Ag) or an alloy such as APC may be applied to the
anode 184. However, the present disclosure may not be limited
thereto. A current corresponding to an image signal is applied to
the anode 184 by the driving transistor 162.
[0133] The bank 186 is disposed on the organic layer 182. The bank
186 is configured to surround each sub-pixel 112. The bank 186 is
configured to have a taper shape. The bank 186 is configured to be
overlapped with at least a part of an edge of the anode 184. The
bank 186 is formed of an organic substance. For example, photo
acryl, polyimide, or the like may be applied to the bank 186.
However, the present disclosure may not be limited thereto.
[0134] The organic light emitting layer 188 is disposed on the
anode 184. The organic light emitting layer 188 is configured to be
entirely deposited in the active area AA. The organic light
emitting layer 188 may be formed of a phosphorescent or fluorescent
material, and may further include an electron transporting layer, a
hole transporting layer, a charge generating layer, and the
like.
[0135] The cathode 190 is disposed on the organic light emitting
layer 188. The cathode 190 is formed of a metallic material having
a low work function or transparent conductive oxide (TCO) with a
very small thickness. The cathode 190 is formed to have a thickness
of 1500 .ANG. or less, preferably, 400 .ANG. or less. If the
cathode 190 is formed to have such thickness, the cathode 190
becomes substantially a semi-transmission and transparent layer.
However, such a cathode 190 has a high electrical resistance.
Therefore, the cathode 190 is configured to be electrically
connected with the second cathode line 134b adjacent thereto.
[0136] A partition wall 192 is disposed to be adjacent to the
sub-pixel 112. The partition wall 192 is formed into a
reverse-taper shape. The reverse-taper shape refers to a shape in
which a width of the partition wall 192 is increased as the
partition wall 192 is upwardly away from a substrate 101. The
partition wall 192 is disposed within an opening part of the bank
186. Such an opening part may be referred to as a "contact area
C/A". A bottom surface of the partition wall 192 is in contact with
a partial area of the second cathode line 134b, and an area of a
top surface of the partition wall 192 is larger than an area of the
bottom surface of the partition wall 192. Therefore, a lower part
of the partition wall 192 that is shaded by the reverse-taper shape
of the partition wall 192 is formed.
[0137] The partition wall 192 is configured to be thicker than the
bank 186. If the partition wall 192 is thicker than the bank 186,
it may be easier to form the partition wall 192 into a
reverse-taper shape.
[0138] Generally, an organic light emitting layer is formed of a
material having a low step coverage. Due to the step coverage of
the organic light emitting layer, the organic light emitting layer
is not deposited on a part shaded by the reverse-taper shape of the
partition wall 192 and a side surface of the partition wall 192,
and the organic light emitting layer is deposited on top surfaces
of the partition wall 192 and the bank 186. Therefore, a physical
space in which the second cathode line 134b and the cathode 190 can
be electrically connected can be secured between the side surface
of the partition wall 192 and the side surface of the bank 186.
Further, a residue 188a of the organic light layer remains on the
partition wall 192.
[0139] The cathode 190 may be in direct contact with a top surface
of the second cathode line 134b exposed between the side surface of
the partition wall 192 and the side surface of the bank 186 in the
contact area C/A. Since the transparent conductive oxide
constituting the cathode 190 has a high step coverage, the cathode
190 can be in contact with the second cathode line 134b exposed
between the side surface of the partition wall 192 and the side
surface of the bank 186. Thus, the cathode 190 and the second
cathode line 134b are electrically connected with each other.
[0140] In some example embodiments, a multi-buffer layer formed of
silicon nitride (SiNx) and silicon oxide (SiOx) may be further
disposed between the first substrate 160 and the driving transistor
162. Since the multi-buffer layer is disposed, it is possible to
protect the driving transistor 162 against impurities and the like
on the first substrate 160 and also possible to protect the driving
transistor 162 against moisture and oxygen.
[0141] In some example embodiments, the driving transistor 162 may
have an inverted-staggered structure.
[0142] In some example embodiments, the driving transistor 162 may
be configured to have a P-type structure. In this case, positions
of the drain electrode 174 and the source electrode 172 of the
driving transistor 162 are reversed. Further, a position of the
capacitor is also changed accordingly.
[0143] In some example embodiments, the transistor insulating film
180 may be removed.
[0144] In some example embodiments, a lens for improving light
extraction efficiency may be additionally formed on the organic
layer 182 in an area where the anode 184 is disposed.
[0145] In some example embodiments, a spacer may be further
disposed on the bank 186. The spacer may be formed of the same
material as that of the bank 186.
[0146] In some example embodiments, a partition wall may be
disposed on a bank. In this case, an island-shaped bank may be
further disposed on a central part of a contact area, and a
partition wall may be disposed on the island-shaped bank.
[0147] In some example embodiments, a partition wall may be
removed. In this case, an organic light emitting layer may be
configured so as not to be entirely deposited, and an area
corresponding to a contact area is patterned by a mask.
[0148] 10. First Anode Line
[0149] Referring to FIG. 1A again, the anode line 130 includes the
first anode line 130a and the second anode line 130b. The anode
line 130 is formed into a comb shape.
[0150] The first anode line 130a of the anode line 130 is disposed
along the upper side surface (first side surface) in the peripheral
area PA of the organic light emitting panel 110. For example, the
first anode line 130a is disposed along the direction of an X-axis
as a major side surface direction of the organic light emitting
panel 110.
[0151] The first anode line 130a is supplied with an anode voltage
ELVDD from the second flexible circuit board 146 and supplies the
anode voltage ELVDD to the second anode line 130b.
[0152] The first anode line 130a includes an extended pad portion
of which a part is bonded to the second flexible circuit board 146.
The extended pad portion of the first anode line 130a is bonded to
the second flexible circuit board 146 by a bonding member, namely
an anisotropic conductive film. However, the bonding member may not
be limited thereto.
[0153] The first anode line 130a is configured to have a relatively
larger width than that of the various lines disposed in the active
area AA in order to minimize a line resistance. For example, a
width L1 of the first anode line 130a may be 1 mm to 3 mm.
Therefore, a difference in line resistance depending on a distance
is negligible. According to the above-described configuration, when
a size of the organic light emitting display panel 110 is
increased, a voltage drop caused by a line resistance of the first
anode line 130a can be minimized.
[0154] A line resistance of the first anode line 130a is relatively
very low and thus explanation thereof will be omitted hereinafter.
However, this does not mean that a resistance of the first anode
line 130a is 0.OMEGA..
[0155] The first anode line 130a may be formed by using some lines
selected from various lines constituting the sub-pixel 112 of the
organic light emitting display panel 110. For example, the first
anode line 130a may be formed of copper (Cu), aluminum (Al), silver
(Ag), molybdenum (Mo), titanium (Ti), gold (Au), transparent
conductive oxide (TCO) or laminates thereof.
[0156] The first anode line 130a is formed of the same material as
that of the data line 120. Although not illustrated in detail in
FIG. 1A, the data line 120 is formed of the same material as that
of the first anode line 130a, and thus, they cannot be disposed on
the same plane. If they are be disposed on the same plane, an
electrical short may occur. Therefore, in an area where the data
line 120 and the first anode line 130a are overlapped, a jump line
using a separate metal layer is formed. For example, a jump line in
the area where the first anode line 130a and the data line 120 are
overlapped may be formed of the same material as that of the gate
line 116. Further, the jump line may be configured to be
electrically insulated by an insulating layer. The insulating layer
may be configured using, for example, an interlayer insulating
film, a gate insulating film, or the like.
[0157] Aline resistance RLine will be described in detail. Each
line is formed of a unique conductive material. Each conductive
material has a resistivity .rho.. Further, the line resistance
RLine is determined by a resistivity .rho., a length L of the line,
a thickness T of the line, and a width W of the line. The line
resistance can be calculated by Equation 1.
Line resistance=Length.times.resistivity.rho./Thickness.times.Width
[Equation 1]
[0158] 11. First Cathode Line
[0159] A cathode line 134 includes the first cathode line 134a and
the second cathode line 134b. The cathode line 130 is formed into a
comb shape.
[0160] The first cathode line 134a of the cathode line 134 is
disposed along the lower side surface (third side surface) opposite
to the upper side surface (first side surface) in the peripheral
area PA of the organic light emitting panel 110. For example, the
first cathode line 134a is disposed along the direction of an
X-axis as the major side surface direction of the organic light
emitting panel 110. Herein, preferably, the first cathode line 134a
and the first anode line 130a may be disposed to be in parallel to
each other.
[0161] The first cathode line 134a is supplied with a cathode
voltage ELVSS from the second flexible circuit board 146 and
supplies the cathode voltage ELVSS to the plurality of second
cathode lines 134b.
[0162] The first cathode line 134a includes an extended pad portion
of which a part is bonded to the second flexible circuit board 146.
The extended pad portion of the first cathode line 134a is bonded
to the second flexible circuit board 146 by a bonding member,
namely an anisotropic conductive film. However, the bonding member
may not be limited thereto.
[0163] The first cathode line 134a is configured to have a
relatively larger width than various lines disposed in the active
area AA in order to minimize a line resistance. For example, a
width L3 of the first cathode line 134a may be 1 mm to 4 mm.
Therefore, a difference in line resistance depending on a distance
is negligible.
[0164] A line resistance of the first cathode line 134a is
relatively very low and thus explanation thereof will be omitted
hereinafter. However, this does not mean that a resistance of the
first cathode line 134a is 0.OMEGA..
[0165] According to the above-described configuration, when the
organic light emitting display panel 110 is increased in size, a
voltage drop caused by a line resistance of the first cathode line
134a can be minimized. Hereinafter, redundant description of a line
resistance will be omitted.
[0166] The first cathode line 134a may be formed by using some
lines selected from various lines constituting the sub-pixel 112 of
the organic light emitting display panel 110. For example, the
first cathode line 134a may be formed of copper (Cu), aluminum
(Al), silver (Ag), molybdenum (Mo), titanium (Ti), gold (Au),
transparent conductive oxide (TCO) or laminates thereof. The first
cathode line 134a is formed of the same material as that of the
anode 184. Otherwise, the first cathode line 134a may be formed of
the same material as that of a reflective layer of the anode
184.
[0167] 12. Second Anode Line
[0168] A plurality of second anode lines 130b of the anode line 130
refer to a plurality of lines which are electrically connected with
the first anode line 130a and extended to the active area AA. For
example, the plurality of second anode lines 130b are configured to
be extended in the direction of a Y-axis perpendicular to the first
anode line 130a. That is, the plurality of second anode lines 130b
are extended from the first side surface to the third side surface.
In other words, the plurality of second anode lines 130b are
extended from one edge of the peripheral area PA to the other edge
of the peripheral area PA opposing the edge so as to be connected
with the plurality of sub-pixels 112. The second anode line 130b
may be formed of a material identical to or different from a
material of the first anode line 130a. Further, the first anode
line 130a and the second anode line 130b may be formed to have a
thickness of 3000 .ANG. to 6000 .ANG..
[0169] The plurality of second anode lines 130b are connected with
the first anode line 130a and extended in the direction of a Y-axis
in the active area AA and then short-circuited at a dead-end of the
active area AA. That is, the second anode lines 130b are one-way
input lines.
[0170] Preferably, the first anode line 130a may be formed of the
same material as that of the data line 120. In particular,
according to the above-described configuration, the second anode
line 130b and the data line 120 can be disposed in parallel to each
other in the direction of a Y-axis. However, the present disclosure
may not be limited thereto.
[0171] Referring to FIG. 1A, the data line 120 and the second anode
line 130b are separated from each other by a predetermined gap and
disposed along the direction of a Y-axis. The second anode line
130b is configured to have a much smaller width than the first
anode line 130a. For example, a width L2 of the second anode line
130b may be 10 .mu.m to 100 .mu.m, and a difference in line
resistance of the second anode line 130b depending on a distance is
worth considering.
[0172] This is because a degree of integration of the sub-pixels
112 in the active area AA is increased, and thus, an area allowing
the width of the second anode line 130b to be increased is actually
limited. Therefore, a line resistance per unit length of the second
anode line 130b is greater than a line resistance per unit length
of the first anode line 130a. That is, a line resistance of the
second anode line 130b is considerably greater than a line
resistance of the first anode line 130a.
[0173] 13. Second Cathode Line
[0174] A plurality of second cathode lines 134b of the cathode line
are electrically connected with the first cathode line 134a and
extended to the active area AA. The plurality of second cathode
lines 134b supply a cathode voltage ELVSS to the active area AA.
For example, the second cathode lines 134b are configured to be
extended in the direction of a Y-axis perpendicular to the first
cathode line 134a. Herein, an input direction of the second cathode
line 134b and an input direction of the second anode line 130b are
opposite to each other. That is, a voltage input direction of the
second anode line 130b and a voltage input direction of the second
cathode line 134b are different from each other and face each
other. Therefore, the plurality of second cathode lines 134b are
extended from the third side surface to the first side surface. In
other words, the plurality of second cathode lines 134b are
extended from the other edge of the peripheral area PA to one edge
of the peripheral area PA opposing the other edge so as to be
connected with the plurality of sub-pixels 112. The second cathode
line 134b may be formed of a material identical to or different
from a material of the first cathode line 134a. Further, the first
cathode line 134a and the second cathode line 134b may be formed to
have a thickness of 800 .ANG. to 1500 .ANG..
[0175] The second cathode line 134b electrically connected with the
first cathode line 134a is extended in a direction opposite to the
second anode line 130b so as to be electrically connected with a
cathode of an organic light emitting diode of each sub-pixel
112.
[0176] The second cathode lines 134b are connected with the first
cathode line 134a and extended in the direction of a Y-axis in the
active area AA and then short-circuited at a dead-end of the active
area AA. That is, the second cathode lines 134b are one-way input
lines.
[0177] According to the above-described configuration, the second
anode lines 130b and the second cathode lines 134b are extended in
the opposite directions and short-circuited at the opposite sides.
Further, the plurality of second anode lines 130b constituting comb
teeth line segments of the comb-shaped anode line 130 and the
plurality of second cathode lines 134b constituting comb teeth line
segments of the comb-shaped cathode line 134 are disposed to cross
each other.
[0178] Preferably, the second cathode line 134b may be formed of
the same material as that of an anode of an organic light emitting
diode OLED. However, the present disclosure may not be limited
thereto.
[0179] Referring to FIG. 1A, the second cathode lines 134b are
separated from each other by a predetermined gap and disposed along
the direction of a Y-axis. The second cathode line 134b is
configured to have a much smaller width than the first cathode line
134a. For example, a width L4 of the second cathode line 134b may
be 10 .mu.m to 400 .mu.m, and a difference in line resistance
depending on a distance is worth considering.
[0180] This is because a degree of integration of the sub-pixels
112 in the active area AA is increased, and thus, an area allowing
the width of the second cathode line 134b to be increased is
actually limited. Therefore, a line resistance per unit length of
the second cathode line 134b is greater than a line resistance per
unit length of the first cathode line 134a. Therefore, a line
resistance of the second cathode line 134b is considerably greater
than a line resistance of the first cathode line 134a.
[0181] A line resistance of the second anode line 130b may be set
to be equal to a line resistance of the second cathode line 134b.
The line resistances may be set by equalizing cross-section areas
of the respective lines.
[0182] For example, the second anode line 130b may be configured to
have a line thickness of 4500 .ANG. and a line width of 10 .mu.m.
In this case, the second cathode line 134b may be configured to
have a line thickness of 1000 .ANG. and a line width of 45 .mu.m.
In this case, if the second anode line 130b and the second cathode
line 134b are formed of the same material, since the cross-section
areas of the respective lines are the same, the line resistances
per unit length are also the same. If the second anode line 130b
and the second cathode line 134b are formed of different materials,
it is possible to set the line resistances to be equal to each
other by substituting a resistivity .rho. using Equation 1.
[0183] 14. Equivalent Circuit of Sub-Pixel
[0184] Referring to FIG. 1D, an equivalent circuit of the first
anode line 130a and the second anode line 130b connected with the
sub-pixel 112 illustrated in FIG. 1A is schematically
illustrated.
[0185] The sub-pixel 112 includes at least an organic light
emitting diode, a driving transistor D.sub.TR, a switching
transistor SW.sub.TR, a capacitor C.sub.ST, a gate line 116 (GATE),
and a data line 120 (DATA). However, it may not be limited
thereto.
[0186] The sub-pixel 112 may further include an initial voltage
(Vint) driver IC for discharging the capacitor C.sub.ST, an
emission duty control circuit additionally disposed between an
anode of the organic light emitting diode and the driving
transistor D.sub.TR and configured to control a duty of a voltage
flowing to the anode, a threshold voltage difference compensation
circuit configured to compensate a difference in a threshold
voltage Vth of the driving transistor D.sub.TR, or the like.
Herein, the threshold voltage difference compensation circuit may
be disposed within the sub-pixel 112 or may be disposed in the
peripheral area PA. However, it may be not limited thereto.
[0187] Each driving transistor D.sub.TR includes a source electrode
S, a drain electrode D, and a gate electrode G.
[0188] The second anode line 130b electrically connected with the
first anode line 130a is extended in the direction of a Y-axis so
as to be electrically connected with the drain electrode D of the
driving transistor D.sub.TR of each sub-pixel 112. However, the
above-described configuration is applied to an N-type transistor.
In the case of a P-type transistor, the second anode line 130b is
electrically connected with the source electrode S of the driving
transistor D.sub.TR of each sub-pixel 112. The capacitor C.sub.ST
is electrically connected with the gate electrode G and the source
electrode S of the driving transistor D.sub.TR.
[0189] Each data line DATA is electrically connected with the gate
electrode G of each driving transistor D.sub.TR so as to apply an
image signal to the driving transistor D.sub.TR. The switching
transistor SW.sub.TR is disposed between the data line DATA and the
driving transistor D.sub.TR. The data line DATA receives an
analogue image signal from the data driver IC 118 and transfers the
analogue image signal to the gate electrode G of the driving
transistor D.sub.TR. Herein, a current capacity flowing to the
organic light emitting diode through the driving transistor
D.sub.TR is controlled according to a voltage value of the image
signal. The image signal applied to the driving transistor D.sub.TR
through the data line DATA may be an image signal modified to
compensate a voltage Vgs according to an increment in the cathode
voltage in the cathode 190 of each of the plurality of sub-pixels
112.
[0190] Each gate line GATE is electrically connected with a gate
electrode of each switching transistor SW.sub.TR. A gate high
voltage VGH and a gate low voltage VGL are applied through the gate
line GATE so as to control the switching transistor SW.sub.TR.
[0191] 15. Line Resistance of Second Anode Line
[0192] Referring to FIG. 1D, a unit line resistance (R.sub.ELVDD)
.OMEGA. of the second anode line 130b can be defined as a line
resistance (R.sub.ELVDD).OMEGA. of the second anode line 130b
corresponding to a length of one sub-pixel 112. Therefore, the
total anode line resistance (RT.sub.ELVDD).OMEGA. is increased
proportionally to the number of the corresponding sub-pixels
112.
[0193] Hereinafter, the following description is made assuming that
the number of the gate lines 116 of the organic light emitting
display panel 110 is N (N is a positive number greater than 0).
[0194] Further, the following description is made assuming that a
gate line at an Nth position is GATE N. For example, a 1st gate
line is GATE 1 and a 100th gate line is GATE 100.
[0195] For example, the total anode line resistance
(RT.sub.ELVDD).OMEGA. of the sub-pixel 112 connected with the 1st
gate line GATE 1 is (R.sub.ELVDD).times.(GATE
1).OMEGA.=(1).times.(R.sub.ELVDD).OMEGA..
[0196] For example, the total anode line resistance
(RT.sub.ELVDD).OMEGA. of the sub-pixel 112 connected with an
(N-2)th gate line GATE N-2 is (R.sub.ELVDD).times.(GATE
N-2).OMEGA.=(N-2).times.(R.sub.ELVDD).OMEGA..
[0197] For example, the total anode line resistance
(RT.sub.ELVDD).OMEGA. of the sub-pixel 112 connected with an
(N-1)th gate line GATE N-1 is (R.sub.ELVDD).times.(GATE
N-1).OMEGA.=(N-1).times.(R.sub.ELVDD).OMEGA..
[0198] For example, the total anode line resistance
(RT.sub.ELVDD).OMEGA. of the sub-pixel 112 connected with an Nth
gate line GATE N is (R.sub.ELVDD).times.(GATE
N).OMEGA.=(N).times.(R.sub.ELVDD).OMEGA..
[0199] Therefore, the total line resistance RT.sub.ELVDD is
gradually increased as the second anode line 130b is away from the
first anode line 130a. Further, as the total line resistance
RT.sub.ELVDD is increased, an anode voltage ELVDD applied to the
anode of the organic light emitting diode is decreased according to
the total anode line resistance RT.sub.ELVDD. Therefore, an anode
voltage of the second anode line 130b is gradually decreased along
the direction of an anode voltage input. A degree of increase in
anode voltage in the second anode line 130b according to a distance
may be set by a line resistance of the second anode line 130b.
[0200] 16. Line Resistance of Second Cathode Line
[0201] Referring to FIG. 1D, a unit line resistance (R.sub.ELVSS)
.OMEGA. of the second cathode line 134b can be defined as a line
resistance (R.sub.ELVSS).OMEGA. of the second cathode line 134b
corresponding to a length of one sub-pixel 112.
[0202] Therefore, the total cathode line resistance
(RT.sub.ELVSS).OMEGA. is increased proportionally to the number of
the corresponding sub-pixels 112.
[0203] For example, the total cathode line resistance
(RT.sub.ELVSS).OMEGA. of the sub-pixel 112 connected with the Nth
gate line GATE N is (R.sub.ELVSS).times.(N-(GATE
N)+1).OMEGA.=(1).times.(R.sub.ELVSS).OMEGA..
[0204] For example, the total cathode line resistance
(RT.sub.ELVSS).OMEGA. of the sub-pixel 112 connected with the (N-1)
th gate line GATE N-1 is (R.sub.ELVSS).times.(N-(GATE
N-1)+1).OMEGA.=(2).times.(R.sub.ELVSS) .OMEGA..
[0205] For example, the total cathode line resistance
(RT.sub.ELVSS).OMEGA. of the sub-pixel 112 connected with the (N-2)
th gate line GATE N-2 is (R.sub.ELVSS).times.(N-(GATE
N-2)+1).OMEGA.=(3).times.(R.sub.ELVSS) .OMEGA..
[0206] For example, the total cathode line resistance
(RT.sub.ELVSS).OMEGA. of the sub-pixel 112 connected with the 1st
gate line GATE 1 is (R.sub.ELVSS).times.(N-(GATE
1)+1).OMEGA.=(N).times.(R.sub.ELVSS).OMEGA..
[0207] Therefore, the total cathode line resistance RT.sub.ELVSS is
gradually increased as the second anode line 134b is away from the
first cathode line 134a. Further, as the total cathode line
resistance RT.sub.ELVSS is increased, a cathode voltage ELVSS
applied to the cathode of the organic light emitting diode is
decreased according to the total cathode line resistance
RT.sub.ELVSS. Therefore, a cathode voltage of the second cathode
line 134b is gradually increased along the direction of a cathode
voltage input. A degree of increase in cathode voltage in the
second cathode line 134b according to a distance may be set by a
line resistance of the second cathode line 134b.
[0208] 17. Total Line Resistance Applied to Organic Light Emitting
Diode
[0209] The gate driver IC 114 of the organic light emitting display
panel 110 activates a single gate line 116 in sequence. Therefore,
all the gate lines other than the gate line activated in FIG. 1D
are inactivated.
[0210] For example, if the 1st gate line GATE 1 is activated, the
other gate lines are not operated. Therefore, the total line
resistance of the second anode line 130b and the second cathode
line 134b connected with the driving transistor D.sub.TR activated
by the 1st gate line GATE 1 can be calculated as follows. The
following description is made assuming that the number of the gate
lines N is 1080.
[0211] For example, the total line resistance of the sub-pixel 112
connected with the 1st gate line GATE 1 is
(1).times.(R.sub.ELVDD)+(1081).times.(R.sub.ELVSS).OMEGA.. That is,
the total second anode line resistance is a second anode unit line
resistance, and the total second cathode line resistance is 1081
second cathode unit line resistances.
[0212] For example, the total line resistance of the sub-pixel 112
connected with a 100th gate line GATE 100 is
(100).times.(R.sub.ELVDD)+(981).times.(R.sub.ELVSS).OMEGA.. That
is, the total second anode line resistance is 100 second anode unit
line resistances, and the total second cathode line resistance is
981 second cathode unit line resistances.
[0213] For example, the total line resistance of the sub-pixel 112
connected with a 1080th gate line GATE 1080 is
(1080).times.(R.sub.ELVDD)+(1).times.(R.sub.ELVSS).OMEGA.. That is,
the total second anode line resistance is 1080 second anode unit
line resistances, and the total second cathode line resistance is a
second cathode unit line resistance.
[0214] For example, the total line resistance of the sub-pixel 112
connected with the Nth gate line GATE N is (GATE
N).times.(R.sub.ELVDD)+(N-(GATE N-1)+1).times.(R.sub.ELVSS).OMEGA..
That is, the total second anode line resistance is N second anode
unit line resistances, and the total second cathode line resistance
is (N-(GATE N-1)+1) second cathode unit line resistances.
[0215] Herein, the second anode unit line resistance R.sub.ELVDD
can be set to be substantially equal to the second cathode unit
line resistance R.sub.ELVSS. In this case, the total line
resistance of the sub-pixel 112 connected with the Nth gate line
GATE N is (R.sub.ELVDD).times.(N+1). Herein, N denotes the total
number of the gate lines 116, and thus, the total line resistance
of each sub-pixel 112 connected with each gate line can be
continuously the same. According to the above-described
configuration, the sum of the total anode line resistance
RT.sub.ELVDD and the total cathode line resistance RT.sub.ELVSS
applied to a certain sub-pixel 112 is uniform regardless of a
position in the direction of a Y-axis. Therefore, a potential
difference (.DELTA.V) between an anode and a cathode is
continuously uniform.
[0216] In some example embodiments, a difference between a unit
line resistance R.sub.ELVDD of an anode and a unit line resistance
R.sub.ELVSS of a cathode may be set to be less than 10% of a unit
line resistance R.sub.ELVDD of an anode line or less than 10% of a
unit line resistance R.sub.ELVSS of a cathode line.
[0217] Further, a difference between a line resistance of the anode
line 130 and a line resistance of the cathode line 134 may be set
to be less than 10% of the line resistance of the anode line 130 or
less than 10% of the line resistance of the cathode line 134.
[0218] FIG. 1E is a graph provided to describe a potential
difference (.DELTA.V) between an anode and a cathode in certain
sub-pixels 112 disposed in the direction of a Y-axis among the
sub-pixels 112 in the active area AA of the organic light emitting
display device 100 when a unit line resistance R.sub.ELVDD of an
anode and a unit line resistance R.sub.ELVSS of a cathode are
substantially equal to each other. Referring to FIG. 1E, it can be
confirmed that a potential difference (.DELTA.V) between an anode
and a cathode of each sub-pixel 112 is continuously uniform
regardless of a position in the direction of a Y-axis. That is, an
increased cathode voltage of the second cathode line 134b is offset
by a decreased anode voltage of the second anode line 130b, and
thus, a deviation in a potential difference between the anode 184
and the cathode 190 in the plurality of sub-pixels 112 can be
compensated.
Comparative Example 1
[0219] FIG. 1F schematically illustrates an equivalent circuit
according to Comparative Example 1. An organic light emitting
display device according to Comparative Example 1 is different from
the organic light emitting display device 100 according to the
example embodiment of the present disclosure in that a first anode
line and a first cathode line are disposed on the same side surface
in a peripheral area of an organic light emitting display panel.
Therefore, a second anode line and a second cathode line are also
input of the same direction.
[0220] In Comparative Example 1, as the second anode line and the
second cathode line are increased in the direction of a Y-axis, the
total anode line resistance RT.sub.ELVDD and the total cathode line
resistance RT.sub.ELVSS are also increased at the same time.
[0221] For example, the total anode line resistance
(RT.sub.ELVDD).OMEGA. of a sub-pixel connected with a 1st gate line
GATE 1 is (R.sub.ELVDD).times.(GATE
1).OMEGA.=(1).times.(R.sub.ELVDD)=.OMEGA., and the total cathode
line resistance (RT.sub.ELVSS).OMEGA. is (R.sub.ELVSS).times.(GATE
1).OMEGA.=(1).times.(R.sub.ELVSS) .OMEGA..
[0222] For example, the total anode line resistance
(RT.sub.ELVDD).OMEGA. of a sub-pixel connected with a 100th gate
line GATE 100 is (R.sub.ELVDD).times.(GATE
100).OMEGA.=(100).times.(R.sub.ELVDD).OMEGA., and the total cathode
line resistance (RT.sub.ELVSS).OMEGA. is (R.sub.ELVSS).times.(GATE
100).OMEGA.=(100).times.(R.sub.ELVSS).OMEGA..
[0223] That is, it can be seen that there is a 100 times difference
in intensity of line resistance between the sub-pixels connected
with the 100th gate line and the 1st gate line.
[0224] For example, the total anode line resistance
(RT.sub.ELVDD).OMEGA. of a sub-pixel connected with a 1080th gate
line GATE 1080 is (R.sub.ELVDD).times.(GATE
1080).OMEGA.=(1080).times.(R.sub.ELVDD).OMEGA., and the total
cathode line resistance (RT.sub.ELVSS).OMEGA. is
(R.sub.ELVSS).times.(GATE 1080)
.OMEGA.=(1080).times.(R.sub.ELVSS).OMEGA..
[0225] That is, it can be seen that there is a 1080 times
difference in intensity of line resistance between the sub-pixels
connected with the 1080th gate line and the 1st gate line.
[0226] FIG. 1G is a graph provided to describe a potential
difference (.DELTA.V) between an anode and a cathode in certain
sub-pixels disposed in the direction of a Y-axis among the
sub-pixels in the active area of the organic light emitting display
device 100 according to Comparative Example 1.
[0227] Referring to FIG. 1G, it can be confirmed that a potential
difference (.DELTA.V) between an anode and a cathode is gradually
decreased as the direction of a Y-axis. Therefore, luminance of the
organic light emitting display device is gradually decreased as the
direction of a Y-axis. As a result, in Comparative Example 1, the
lower side surface (third side surface) looks dark and luminance
uniformity is considerably decreased.
Comparative Example 2
[0228] FIG. 1H schematically illustrates an equivalent circuit
according to Comparative Example 2. An organic light emitting
display device according to Comparative Example 2 is different from
the organic light emitting display device according to Comparative
Example 1 in that a first anode line and a first cathode line are
disposed on both side surfaces (a first side surface and a third
side surface) in a peripheral area of an organic light emitting
display panel. Therefore, a second anode line and a second cathode
line are also input of both directions.
[0229] In Comparative Example 2, since an anode voltage ELVDD and a
cathode voltage ELVSS are applied from the both side surfaces (the
first side surface and the third side surface), a potential
difference (.DELTA.V) between an anode and a cathode is decreased
as proceeding toward a central part of an active area.
[0230] FIG. 1I is a graph provided to describe a potential
difference (.DELTA.V) between an anode and a cathode in certain
sub-pixels disposed in the direction of a Y-axis among the
sub-pixels in the active area of the organic light emitting display
device 100 according to Comparative Example 2.
[0231] Referring to FIG. 1I, it can be confirmed that a potential
difference (.DELTA.V) between an anode and a cathode is gradually
decreased toward the central part of the active area. Therefore,
the central part of the active area looks dark and luminance
uniformity considerably deteriorates.
[0232] FIG. 2 is a schematic plan view of an organic light emitting
display device according to another example embodiment of the
present disclosure.
[0233] In an organic light emitting display device 200 according to
another example embodiment of the present disclosure, a gate driver
IC 214 is implemented as a gate-driver in panel (GIP) in order to
implement a narrow bezel. The gate driver IC 214 is used to form a
plurality of sub-pixels 112 of an organic light emitting display
panel 210 and formed in a peripheral area PA of the organic light
emitting display panel 210 at the same time.
[0234] The gate driver IC 214 includes a plurality of shift
registers, and the shift registers are connected with the
respective gate lines 116. The gate driver IC 214 receives a gate
start pulse (GSP) and a plurality of clock signals from the data
driver IC 118, and the shift registers of the gate driver IC 214
shift the gate start pulse (GSP) in sequence and activate the
plurality of sub-pixels 112 respectively connected with the gate
lines 116.
[0235] If the gate-driver in panel 214 is disposed, the
semiconductor chip-shaped gate driver IC 114, an anisotropic
conductive film, and a corresponding pad may be removed, and it is
possible to implement a narrow bezel having a smaller width than a
bezel of the semiconductor chip-shaped gate driver IC.
[0236] Except for the above-described matters, the organic light
emitting display device 200 according to another example embodiment
of the present disclosure is the same as the organic light emitting
display device 100 according to the example embodiment of the
present disclosure. Therefore, redundant description thereof will
be omitted.
[0237] In some example embodiments, the gate driver IC may be
formed only on one side surface (second side surface) of the
organic light emitting display panel. If the gate driver IC formed
only on one side surface (second side surface) is disposed, it is
possible to implement a narrow bezel having a smaller width on the
other side surface (fourth side surface) than a bezel on the side
surface (second side surface).
[0238] In some example embodiments, the gate-driver in panel (GIP)
illustrated in FIG. 2 can be applied to all the other example
embodiments.
[0239] FIG. 3 is a schematic plan view of an organic light emitting
display device according to yet another example embodiment of the
present disclosure.
[0240] In an organic light emitting display device 300 according to
yet another example embodiment of the present disclosure, the first
anode line 130a and a first cathode line 334a of a cathode line 334
are disposed on an upper side surface (first side surface) of an
organic light emitting display panel 310. Herein, the first cathode
line 334a is disposed to surround a peripheral area PA of the
organic light emitting display panel 310. That is, the first
cathode line 334a may be disposed along the first side surface, a
second side surface, a third side surface, and a fourth side
surface of the organic light emitting display panel 310, or may be
configured to have a square shape or a ring shape. Herein, a length
of the first cathode line 334a is longer than a length of the first
anode line 130a, and thus, preferably, a width of the first cathode
line 334a is set to be greater than a width of the first anode line
130a so as not to increase a line resistance. Therefore, the width
of the first cathode line 334a is configured to be greater than the
width of the first anode line 130a. The second anode line 130b and
the second cathode line 134b are extended from the first anode line
130a and the first cathode line 134a, respectively.
[0241] Since the first anode line 130a and the first cathode line
334a of the organic light emitting display device 300 are disposed
on the upper side surface (first side surface) of the organic light
emitting display panel 310, a second flexible circuit board 346 is
configured to supply an anode voltage ELVDD and a cathode voltage
ELVSS at the same time.
[0242] According to the above-described configuration, the organic
light emitting display device 300 has an effect of removing the
data circuit board 142 and the second flexible circuit board 146
disposed on the lower side surface (third side surface) of the
organic light emitting display device 100.
[0243] According to the above-described configuration, the organic
light emitting display device 300 can be a transparent organic
light emitting display device. To be specific, in order to input an
anode voltage ELVDD and a cathode voltage ELVSS from the opposite
directions as illustrated in FIG. 1B, various circuit boards and
lines need to be disposed on a rear surface of the organic light
emitting display panel 110. However, in the organic light emitting
display panel 310 according to yet another example embodiment of
the present disclosure, the upper side surface (first side surface)
includes circuit boards and lines, and thus, various circuit boards
and lines do not need to be disposed on a rear surface of the
organic light emitting display panel 310. Therefore, even if the
organic light emitting display panel 310 has light transparency,
circuit boards and lines can be invisible on the rear surface.
[0244] Except the above-described matters, the organic light
emitting display device 300 according to yet another example
embodiment of the present disclosure is the same as the organic
light emitting display device 100 according to the example
embodiment of the present disclosure. Therefore, redundant
description thereof will be omitted.
[0245] In some example embodiments, the first anode line and the
first cathode line may be reversed. To be specific, the first anode
line may be disposed to surround the peripheral area PA of the
organic light emitting display panel and the first cathode line may
be disposed along the upper side surface (first side surface) of
the organic light emitting display panel.
[0246] In some example embodiments, a light transmission part for
providing light transparency to sub-pixels 412 of an organic light
emitting display panel 410 may be further included.
[0247] FIG. 4A is a schematic plan view of an organic light
emitting display device according to still another example
embodiment of the present disclosure.
[0248] An organic light emitting display device 400 according to
still another example embodiment of the present disclosure is an
example of a modification of the organic light emitting display
device 300 according to yet another example embodiment of the
present disclosure.
[0249] The first anode line 130a and a first cathode line 434a of
the organic light emitting display device 400 are formed of the
same material. Therefore, the first anode line 130a and the first
cathode line 434a cannot be overlapped with each other, where the
first cathode line 434a is separated from an area where the first
anode line 130a and the first cathode line 434a are overlapped.
That is, the first cathode line 434a is divided into at least two
parts in a peripheral area PA and the divided parts are connected
by a jump line 437.
[0250] FIG. 4B is a cross-sectional view of the sub-pixel 412 of
the organic light emitting display device 400 according to still
another example embodiment of the present disclosure illustrated in
FIG. 4A.
[0251] A second cathode line 434b of a cathode line 434 includes at
least two metal layers, and includes, for example, a second cathode
first line 434c and a second cathode second line 434d as
illustrated in FIG. 4B.
[0252] The second cathode first line 434c is formed of the same
material as the anode 184. The second cathode second line 434d is
formed of the same material as that of the second anode line 130b.
The first cathode first line 434c and the second cathode second
line 434d are connected with each other through a third contact
hole 434e.
[0253] According to the above-described configuration, it is
possible to reduce thickness of the first cathode line 434a. To be
specific, the first cathode line 434a may be formed of the same
material as that of the data line 120. Therefore, the first cathode
line 434a can be formed to have a greater thickness, and thus, the
width L1 of the first cathode line 434a can be reduced.
[0254] According to the above-described configuration, it is
possible to reduce a width L4 of the second cathode line 434b. To
be specific, a cross-section area can be increased by the second
cathode first line 434c and the second cathode second line 434d,
and thus, the width of the second cathode line 434b can be
reduced.
[0255] Except the above-described matters, the organic light
emitting display device 400 according to still another example
embodiment of the present disclosure is the same as the organic
light emitting display device 300 according to still another
example embodiment of the present disclosure. Therefore, redundant
description thereof will be omitted.
[0256] In some example embodiments, the first anode line and the
first cathode line may be reversed. To be specific, the first anode
line may be disposed to surround the peripheral area PA of the
organic light emitting display panel and the first cathode line may
be disposed along the upper side surface (first side surface) of
the organic light emitting display panel.
[0257] FIG. 5A is a schematic plan view of an organic light
emitting display device according to still another example
embodiment of the present disclosure.
[0258] An organic light emitting display device 500 according to
still another example embodiment of the present disclosure is a
modified example of the organic light emitting display device 100
according to an example embodiment of the present disclosure.
[0259] In the organic light emitting display device 500, an image
signal compensation unit 550 is disposed on a control circuit board
542.
[0260] The image signal compensation unit 550 is configured to
store voltage compensation data. The voltage compensation data may
be stored in a memory within the image signal compensation unit 550
or in a separate external memory. The voltage compensation data are
configured to store compensation values respectively corresponding
to the sub-pixels 112. On the basis of line resistance information
of the first cathode line 134 within the active area AA, the
voltage compensation data include information for compensating each
of the cathode voltage increments (.DELTA.ELVSS) corresponding to
the sub-pixels 112. The voltage compensation data may be determined
on the basis of design values of the lines in the organic light
emitting display panel 110. For example, the design values of the
lines can be calculated on the basis of a width, thickness, length
of a line, resistivity .rho. of a line, and positional information
of each sub-pixel 112 to be compensated. Otherwise, information of
the total cathode line resistance (RT.sub.ELVSS).OMEGA. or the
second cathode unit line resistance (RE.sub.LVSS) already
calculated when the panel is designed may be used.
[0261] If a cathode voltage ELVSS is modified by a line resistance,
a potential difference between the gate electrode G and the source
electrode S in the driving transistor D.sub.TR, i.e., a gate
electrode-source electrode potential difference (Vgs), may be
modified. Therefore, luminance may be partially modified.
[0262] The image signal compensation unit 550 modifies an image
signal on the basis of the stored voltage compensation data, and
sends a compensated image signal to the data driver IC 118. In
example embodiments, the image signal is compensated proportionally
to the increment in the cathode voltage ELVSS.
[0263] In some example embodiments, the image signal compensation
unit 550 may be configured to calculate voltage compensation data
while the organic light emitting display device 100 is operated.
The image signal compensation unit 550 stores only the design
values of the lines in the organic light emitting display panel 110
and the design values are required for calculation of voltage
compensation data. Further, the calculation of voltage compensation
data is performed while the organic light emitting display device
is operated. In particular, according to the above-described
configuration, there is an advantage in that voltage compensation
data may not be stored. Also, there is an advantage of being easily
applicable to organic light emitting display panels of various
sizes and shapes.
[0264] In some example embodiments, the image signal compensation
unit 550 can store only voltage compensation data corresponding to
a row of sub-pixels 112 disposed in a vertical direction (Y-axis).
In particular, as illustrated in FIG. 1D, since a plurality of rows
of sub-pixels 112 has similar line resistance characteristics, by
setting voltage compensation data of a row of sub-pixels 112 as
reference voltage compensation data, it is possible to compensate
other rows of sub-pixels 112.
[0265] In some example embodiments, when the image signal
compensation unit 550 compensates the plurality of rows of
sub-pixels 112 with reference voltage compensation data
corresponding to a row of sub-pixels 112, offset values for
respectively compensating differences among the sub-pixels 112 in
each row may be further included. In particular, a voltage supply
pad may be included.
[0266] In some example embodiments, the image signal compensation
unit 550 can exclude or add some information of the design values
of some lines for calculation. According to the above-described
configuration, the image signal compensation unit 550 updates only
information optimized for an organic light emitting display panel,
and thus, has an advantage of being able to increase compensation
efficiency.
[0267] In some example embodiments, the voltage compensation data
in the image signal compensation unit 550 may be configured in the
form of a look-up table.
[0268] In some example embodiments, the image signal compensation
unit 550 may be configured to be included in the data driver IC
118. Otherwise, the image signal compensation unit 550 may be
disposed on the data circuit board 140. That is, the image signal
compensation unit 550 is not limited to be disposed on the control
circuit board 542, but can be disposed or included in other various
components.
[0269] FIG. 5B is a schematic equivalent circuit diagram provided
to describe a resistance value of each sub-pixel in an organic
light emitting display device to which a compensated image signal
is supplied according to still another example embodiment of the
present disclosure disclosed in FIG. 5A.
[0270] Each sub-pixel 112 includes at least an organic light
emitting diode, a driving transistor D.sub.TR, a switching
transistor SW.sub.TR, a capacitor C.sub.ST, a gate line GATE, and a
data line DATA. Such a structure may be classified as a 2T1C
structure including two transistors and one capacitor C.sub.ST.
[0271] A first image signal C-Data1 compensated by the image signal
compensation unit 550 is applied to the gate electrode G of the
driving transistor D.sub.TR. Therefore, a potential difference
between the gate electrode G and the source electrode S, i.e., a
gate electrode-source electrode potential difference (Vgs), may be
compensated. Therefore, luminance may be further improved.
[0272] FIG. 5C is a schematic graph provided to describe a
potential difference between anode and cathode of each sub-pixel
and a compensated image signal in the organic light emitting
display device according to still another example embodiment of the
present disclosure.
[0273] The compensated first image signal C-Data1 in FIG. 5C is
illustrated as compensated data obtained by increasing voltage of
an image signal applied to each sub-pixel 112 by a cathode voltage
increment (.DELTA.ELVSS) corresponding to each sub-pixel 112 having
a 2T1C sub-pixel structure. Herein, since all of image signals
before compensation display the same luminance, the same voltage
needs to be applied thereto. However, since the cathode voltage
ELVSS is increased, the compensated first image signal C-Data1 is
directly proportional to the increase in the cathode voltage
ELVSS.
[0274] For example, the compensated first image signal C-Data1
according to the voltage compensation data applied to one of the
sub-pixels 112 may be described with reference to Equation 2.
(C-Data1)=Image signal+Cathode voltage increment(.DELTA.ELVSS)
[Equation 2]
[0275] The C-Data1 is a compensated image signal applied through a
data line. The image signal in Equation 2 is an analogue image
signal converted from a digital image signal input from an external
system into a voltage value by a data driver IC. The cathode
voltage increment (.DELTA.ELVSS) refers to a voltage value
increased by a line resistance.
[0276] That is, if a cathode voltage ELVSS of a certain 2T1C
sub-pixel 112 is increased by 0.1 V, the image signal compensation
unit 550 generates C-Data1 by compensating a voltage value of an
image signal applied to the sub-pixel 112 using the voltage
compensation data such that the image signal can be increased by
0.1 V.
[0277] That is, the voltage compensation data can be realized by
adding an increment of a cathode voltage ELVSS corresponding to
each sub-pixel 112 to an image signal applied to the sub-pixel 112.
The compensated first image signal C-Data1 is applied to the gate
electrode G of the driving transistor D.sub.TR of the sub-pixel
112. Therefore, luminance uniformity of an organic light emitting
display device can be further improved with the voltage
compensation data.
[0278] Except the above-described matters, the organic light
emitting display device 500 according to still another example
embodiment of the present disclosure is the same as the organic
light emitting display device 100 according to an example
embodiment of the present disclosure. Therefore, redundant
description thereof will be omitted.
[0279] FIG. 6A is a schematic plan view of an organic light
emitting display device including a data driver IC according to
still another example embodiment of the present disclosure. An
organic light emitting display device 600 according to still
another example embodiment of the present disclosure is a
modification example of the organic light emitting display device
100 according to an example embodiment of the present disclosure.
FIG. 5B is a schematic equivalent circuit diagram provided to
describe a resistance value of each sub-pixel in an organic light
emitting display device to which a compensated image signal is
supplied according to still another example embodiment of the
present disclosure disclosed in FIG. 5A.
[0280] Each sub-pixel 612 includes at least an organic light
emitting diode, a driving transistor D.sub.TR, a switching
transistor SW.sub.TR, a sensing transistor SEN.sub.TR, a capacitor
C.sub.ST, a gate line GATE, a data line DATA, a reference line REF,
a sensing line SENS. Such a structure may be classified as a 3T1C
structure including three transistors and one capacitor.
[0281] A second image signal C-Data2 compensated by the image
signal compensation unit 550 is applied to the gate electrode G of
the driving transistor D.sub.TR. Therefore, a potential difference
between the gate electrode G and the source electrode S, i.e., a
gate electrode-source electrode potential difference (Vgs), may be
compensated. Since the potential difference between the gate
electrode G and the source electrode S is compensated, luminance
uniformity can be further improved.
[0282] Further, since the sub-pixel 612 has a 3T1C structure, even
if a cathode voltage ELVSS is increased in the same manner as
illustrated in FIG. 5B, the voltage compensation data are not
directly proportional to a cathode voltage increment
(.DELTA.ELVSS). To be specific, the voltage compensation data refer
to data obtained by reflecting an inherent capacitance C.sub.OLED
of the organic light emitting diode and a capacitance C.sub.st of
the capacitor C.sub.ST to the cathode voltage increment
(.DELTA.ELVSS).
[0283] For example, the compensated second image signal C-Data2
according to the voltage compensation data applied to one of the
sub-pixels 612 may be described with reference to Equation 3.
(C-Data2)=Image signal+Cathode voltage
increment(.DELTA.ELVSS).times.C.sub.OLED/C.sub.st. [Equation 3]
[0284] The C-Data2 is a compensated image signal applied through a
data line. The image signal in Equation 3 is an analogue image
signal converted from a digital image signal input from an external
system into a voltage value by a data driver IC 618. The cathode
voltage increment (.DELTA.ELVSS) refers to a voltage value
increased by a line resistance. The C.sub.OLED represents an
inherent capacitance of the organic light emitting diode. The
C.sub.st represents a capacitance of the capacitor C.sub.ST.
[0285] In addition, in the 3T1C structure, the sensing transistor
SEN.sub.TR is further disposed in order to compensate a threshold
voltage difference (.DELTA.Vth) of the driving transistor D.sub.TR.
Further, the sensing transistor SEN.sub.TR transfers information of
the threshold voltage difference (.DELTA.Vth) of each driving
transistor D.sub.TR to the reference line REF by a signal applied
to the sensing line SENS. The reference line REF may be connected
with the data driver IC 618. Herein, the data driver IC 618 senses
a threshold voltage difference (.DELTA.Vth) of the driving
transistor D.sub.TR, and a threshold voltage difference
compensation circuit may be configured to compensate the sensed
difference.
[0286] FIG. 6C is a schematic graph provided to describe a
potential difference between anode and cathode of each modified
sub-pixel and a compensated image signal in the organic light
emitting display device according to still another example
embodiment of the present disclosure.
[0287] The compensated second image signal C-Data2 in FIG. 6C is
illustrated as compensated data obtained by increasing a voltage of
an image signal. An image signal is then applied to each sub-pixel
612 by a cathode voltage increment (.DELTA.ELVSS) corresponding to
each sub-pixel 612 having a 3T1C sub-pixel structure. Herein, since
all of image signals before compensation display the same
luminance, the same voltage needs to be applied thereto. However,
since the cathode voltage ELVSS is increased, the compensated
second image signal C-Data2 is compensated according to an increase
in the cathode voltage ELVSS and a capacitance ratio between the
organic light emitting diode and the capacitor.
[0288] That is, the image signal compensation unit 550 increases a
cathode voltage ELVSS of a certain sub-pixel 112 by 0.1 V, and
modifies a voltage value of an image signal applied to the
sub-pixel 112. The modification is achieved by using voltage
compensation data obtained by reflecting an inherent capacitance
C.sub.OLED of the organic light emitting diode and a capacitance
C.sub.st of the capacitor C.sub.ST to 0.1 V. Therefore, luminance
uniformity can be further improved with the voltage compensation
data.
[0289] In some example embodiments, the second image signal C-Data2
compensated in the data driver IC 618 may be configured to include
all of a compensation value according to the increase in the
cathode voltage ELVSS and a compensation value for compensating the
threshold voltage difference (.DELTA.Vth) of each driving
transistor D.sub.TR.
[0290] For example, a compensated image signal C-Data3 according to
voltage compensation data applied to one of the sub-pixels 612 may
be described with reference to Equation 4.
(C-Data3)=Image signal+Cathode voltage
increment(.DELTA.ELVSS).times.C.sub.OLED/C.sub.st+(.DELTA.Vth)
[Equation 4]
[0291] Except the above-described matters, the organic light
emitting display device 600 according to still another example
embodiment of the present disclosure is the same as the organic
light emitting display device 500 according to still another
example embodiment of the present disclosure. Therefore, redundant
description thereof will be omitted.
[0292] Although the example embodiments of the present disclosure
have been described in detail with reference to the accompanying
drawings, the present disclosure is not limited thereto and may be
embodied in many different forms without departing from the
technical concept of the present disclosure. Therefore, the example
embodiments of the present disclosure are provided for illustrative
purposes only but not intended to limit the technical concept of
the present disclosure. The scope of the technical concept of the
present disclosure is not limited thereto. The protective scope of
the present disclosure should be construed based on the following
claims, and all the technical concepts in the equivalent scope
thereof should be construed as falling within the scope of the
present disclosure.
* * * * *